1. Field of the Invention
The invention relates generally to the monitoring of activity of a data processing system and more specifically to the use of programmable hit matrices (PHM's) or memories for comparing information being transferred within the system with predetermined bits stored in the PHM for generating statistical data.
2. Description of the Prior Art
The throughput of prior art data processing systems were measured by writing software routines and measuring the time it took for the system to execute the routines. When new systems were designed, the same software routines were executed on the new and the old systems and the difference in running time noted. Central processor unit (CPU) limited and peripheral limited software routines were used to compare the throughput of the old and new systems. The execution time of a particular instruction was determined with an oscilloscope.
Monitoring devices were developed having counters and magnetic tape drives. Typical of these devices is the NCR Comten Model 7916. Probes coupled to the monitoring device are placed on the backboard pins of the system being monitored. The signals received by the monitoring device are wired to logic elements such as AND gates, OR gates, inverters and counters to develop performance data. These monitoring devices present a number of problems. Often many signals, each requiring a probe, are needed for the analysis. The pins on the system being monitored are difficult to locate, and the probes easily fall off. The prior art has the requirement of providing probe points for certain signals which increase the system cost.
It is also desirable for customer personnel to take performance measurements, particularly when the customers write their own software. Here the customer must rely on maintenance personnel to determine which backboard signals are needed and to place the probes on the proper backboard pins.